[Boatanchors] Cardwell 54
Richard Knoppow
1oldlens1 at ix.netcom.com
Fri Apr 30 01:52:04 EDT 2021
Thank you so much Manualman and Robert Nichols. The answers
seem to lie here. I remember Gilfillan Brothers very well, we
used to drive past their factory often. I think we had a
Gilfillan radio when we first moved to L.A.
The Cardwell receiver seems to have some things in common
with the Pierson. Perhaps the same ideas and features occurred to
different designers. I will do some reading and will perhaps have
more questions.
As far as Solar, they disappeared from the catalogs rather
suddenly. I can well believe there were financial troubles. For a
year or so before vanishing the ads changed the name from
"manufacturing" to "sales" suggesting a reorganization. This is
more than I've found previously.
On 4/29/2021 5:50 PM, Robert Nickels wrote:
> On 4/29/2021 4:50 PM, Richard Knoppow wrote:
>> A lot of smaller businesses just vanished, perhaps true of
>> Pierson.
>
> True but it's a tangled web. From the N7RK website:
> "California was home to a number of manufacturers of
> communications receivers in the 1930's. Names such as
> Gillfillan Brothers, Patterson, Sargent and the Breting Radio
> Manufacturing Company in Los Angeles, California were some of
> the better known companies. Emmitt Patterson started the
> Patterson Electric in 1919. The chief engineer was Ray Gudie
> who also designed the Breting receivers. Ray Gudie left
> Patterson during the design of the PR-12, Karl Pierson joined
> the company in 1934 and was instrumental in the design of the
> PR-15 and PR-16 receivers. Patterson built receivers from
> 1935-1940. The Patterson receivers were high end receivers with
> high tube counts, chrome chassis', crystal filters and many
> other features not available on Hallicrafters and National
> radios of the same vintage. All the Patterson chassis' were
> manufactured in the Gillfillan plants. Patterson went out of
> business in 1939."
>
> Karl E. Pierson and Mr.DeLaplane formed Pierson-DeLane
> (shortening the latter's name) in 1937. In 1939 they started
> concentrating on two-way radio equipment, e.g. police radio.
> The Company was wound up in 1943 after taking over
> manufacturing of the PR-15. More here:
> http://www.radiodx.com/articles/technical/equipment-reviews/paterson/
>
>
> All of which is to set the stage for Karl Pierson's new
> post-war venture to manufacture a high-end communications
> receiver, the KP-81. That did happen - I know of three
> including my own, which is still awaiting re-assembly. The
> definitive work on the KP-81 has been written by my buddy John
> Vendeley K9WT, who is an excellent engineer and who has more
> patience and admiration for Karl Pierson's design skills than I
> do. It is a case where the electrical design was very
> advanced, the mechanical design is robust and very attractive
> - but the lack of consideration for maintenance and
> documentation is a critical weakness.
>
> The receiver is modular, which is great as far as it goes,
> which unfortunately does not include the RF front-end. All
> the front-end components are invisible and inaccessible,
> trapped inside a two-piece metal enclosure that requires
> unsoldering of 16 hardwired connections, then prying apart the
> two halves which are connected via component leads and stiff
> solid wire interconnects. Then the aged resistors and
> capacitors can be replaced and the process reversed, which is
> the stage mine is at. The cast coil drawer is extremely well
> built but also very heavy and fits into the chassis with very
> little room to spare, so great care and gymnastics are required
> to avoid damaging the contact clips in the process. I've
> replaced the 20 or so caps in an SP-600 and felt that was bad
> at the time, but the KP-81 takes it to a whole new level.
>
> The receiver was shipped with a schematic that had reference
> designations but no values, nor was a bill of materials
> provided that correlated those designators with actual
> values. Pierson evidently felt that component values might
> change over time and it wasn't important to inform customers of
> what they were. He also drew the schematic with the tubes
> rotated 90 degrees and without pin numbers which just makes it
> that much more fun to read. John, with help from Rodger WQ9E
> have filled in those blanks but working on a KP-81 requires a
> lot patience - aided by a healthy vocabulary!
>
> Everything you ever wanted to know about the design and
> restoration of the KP-81 can be found in John's document, here:
>
> http://jptronics.org/pierson%20kp-81/index.html
>
> 73, Bob W9RAN
>
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--
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL
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